This invention relates to new 1,2,3-thiadiazole-5-yl urea derivatives, processes for making these compounds, plant growth and defoliating agents containing these compounds as active substances and processes for using these compounds to achieve plant growth and defoliating action.
1,2,3-thiadiazole-5-yl-urea derivatives possessed of plant growth and defoliating activity are already known (DE-OS No. 2,214,632; DE-OS No. 2,506,960). Thus 1-phenyl-3-(1,2,3-thiadiazole-5-yl)-ureas are known as cotton plant defoliants. It is, however, desired to provide more effective defoliants and/or plant growth regulators than these known compounds.
It is, therefore, an essential object of this invention to provide new, 1,2,3-thiadiazole-5-yl-urea derivatives which are structural analogs of the known cotton defoliants but which are more effective in their defoliating activity than the known compounds and that even when used in smaller quantities.
According to the invention, this and other objects and advantages are achieved through the provision of 1,2,3-thiadiazole-5-yl-urea derivatives of the formula ##STR2## wherein R.sub.1 is hydrogen or a C.sub.1 -C.sub.4 alkyl group which may be interrupted by one or more sulfur or oxygen atoms, R.sub.2 is a C.sub.1 -C.sub.4 alkyl group which may be interrupted by one or more sulfur or oxygen atoms, a cycloaliphatic hydrocarbon group which may be substituted by one or more alkyl groups, an aromatic hydrocarbon group which may be substituted by one or more members of the group consisting of alkyl, halogen, alkylthio, alkoxy, trifluoromethyl and nitro or a heterocyclic hydrocarbon group which may be substituted containing at least one nitrogen atom, R.sub.3 is hydrogen, a C.sub.1 -C.sub.10 alkyl group which may be substituted, a C.sub.2 -C.sub.8 alkenyl, an aryl-C.sub.1 -C.sub.2 -alkyl, a C.sub.3 -C.sub.8 -cycloaliphatic hydrocarbon group which may be substituted with one or more C.sub.1 -C.sub.6 alkyl groups, or an aromatic hydrocarbon group which may be substituted for one or more members of the group consisting of C.sub.1 -C.sub.6 -alkyl, halogen, C.sub.1 -C.sub.6 -alkoxy and trifluoromethyl and X is oxygen or sulfur.
The compounds of the invention are excellently suitable for defoliating cotton plants and this regard markedly surpass the known agents of analogous structure and activity. The use of mechanical cotton pickers for picking the cotton balls is thereby made possible.
On normal cotton plants which are not treated with defoliating agents, the bolls on the lower branches open first while the bolls on the upper branches continue to open slowly over a period of as long as two months from the time when picking of the lower bolls is desirable. The majority of the leaves remain attached to the plant and cause green stains on the cotton when mechanical cotton pickers are employed. In addition, the leaves high on the plant shade the lower bolls from sunlight an air resulting in excessive boll rot. At times, 15% of the cutton crop has been lost because of this boll rot. Without the use of defoliating agents, numerous hand pickings are necessary to prevent boll rot and staining.
It is the discovery of this invention that the foliage of cotton plants may be treated with many types of the herein described 1,2,3-thiadiazole-5-yl-urea derivatives with the result that the leaves are shed.
The compounds of the invention are also excellently suitable for regulating plant growth by retarding the vegetative growth thereof. Observation of the operation of the defoliant ingredient indicates that when properly applied a true hormonetype action is involved, and the defoliant operates by a true translocation within the plant system. The regulation of the plant growth which is achieved by application of the compounds of the invention is visually recognized and can be appreciated by a change in the plant size, particularly in its height, its shape or color or by the change in structure of the treated plant or of its parts, i.e., roots, stems, buds, leaves, etc.
For example, the following changes in the plant may be observed in addition to the defoliation:
Inhibition of vertical growth. PA1 Inhibition of root development. PA1 Stimulation of bud development. PA1 Intensification of the plant coloration, etc.
The compounds of the invention may be used either alone or in a mixture with one another or with other active substances. Optionally, other plant protection or pest control agents, such as fungicides, nematocides, or other agents may be added, according to the desired purpose. The addition of fertilizers may also be desirable or preferable.
Depending on the purpose of use, other substances may also be added, for example non-phytotoxic components which can produce with herbicides a synergistic increase of action, such as wetting agents, emulsifiers, solvents, oily additions and the like.
The quantities used for the desired regulation of plant growth are, as a rule 0.05 to 5 kg active substance per hectare.
The manner of the growth regulating effect, however, depends on the treatment time and, not least on the type of plant involved. Against certain weeds in the early stage or the start of sprouting, the inhibition may occur in a manner which equals, for example total inhibition of development of a wasteland flora including shrubbery. The chemical compounds of the invention can be used also where it is desired not to fully destroy flora at once, but to maintain it in a vegetative low growth stage.
Appropriately, the active substances according to the invention or their mixtures are used in the form of suitable preparations, such as powders, scatters, granulates, solutions, emulsions or suspensions, with the addition of a liquid and/or solid vehicle or diluent and also of a wetting, adhesive emulsifying and/or dispersing agent.
Suitable liquid vehicles are water, aliphatic and aromatic hydrocarbons, such as benzene, toluene, xylene, cyclohexanone, isophorone, dimethylformamide, and mineral oil fractions.
As solid vehicles, there come into consideration the mineral earths, such as siliceous clay, silica gel, talc, kaolin, attaclay, limestone, silicic acid and plant products, such as flours.
Among surface active substances there may be mentioned calcium-lignin sulfonate, polyoxyethyleneoctylphenolether, naphthelene-sulfonic acids and their salts, phenosulfonic acids and their salts, formaldehyde condensates, fatty alcohol sulfates and substituted benzene sulfonic acids and their salts.
The proportion of the active substance or substances in the various preparations may vary within wide limits. The agents contain for example about 5% to 95% by weight of active substances, about 95% to 5% by weight of liquid or solid vehicles as well as possibly up to 20% by weight of surface active substances.
The application of the agents may be effected in the usual manner, such as with water as vehicle in total spray quantities of 100 to 5000 liters/ha. An application of the agents in the so-called "ultra-low-volume process" is likewise possible, as is their application in the form of so-called microgranulates.
The type and manner of achieving the desired plant growth regulation is of course dependent on the treatment time, i.e. at what time in the plant life cycle it is carried out, the type of plant, the concentration of the active agent, etc. but this is all part of the art.
Compounds of the invention, which have been found to be particularly effective are those in which in formula I R.sub.1 is hydrogen, C.sub.1 -C.sub.4 -alkyl as for example methyl, ethyl, isopropyl, propyl or butyl, R.sub.2 is C.sub.1 -C.sub.4 -alkyl as for example methyl or ethyl, C.sub.5 -C.sub.8 cyclo-alkyl as for example cyclopentyl, cyclohexyl or methylcyclohexyl, aryl as for example phenyl, halogenophenyl, C.sub.1 -C.sub.4 -alkylphenyl, C.sub.1 -C.sub.4 -alkoxyphenyl, nitrophenyl or trifluoromethylphenyl, R.sub.3 is hydrogen, C.sub.1 -C.sub.10 -alkyl as for example methyl, ethyl, propyl, n-butyl, 1-ethylpropyl, tert.-butyl, n-heptyl, n-nonyl or n-decyl, fluoromethyl, methoxymethyl, phenoxymethyl, 1-phenoxyethyl, 2-phenoxyethyl, or (2,4-dichlorophenoxy)-methyl, C.sub.2 -C.sub.8 -alkenyl as for example 2-butenyl, 2-methyl-2-propenyl or propene-1-yl, aryl-C.sub.1 -C.sub.2 -alkyl as for example benzyl, 4-chlorobenzyl, C.sub.3 -C.sub.8 -cycloalkyl as for example cyclopropyl, cyclopentyl, cyclohexyl or methylcyclohexyl, phenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, aryl as for example 2,4-dichlorophenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 3-nitrophenyl, 4-nitrophenyl, 2-methoxyphenyl, 4-methoxyphenyl, 1-naphthyl, 2-naphthyl or 2-furyl and X is oxygen or sulfur.
The compounds of the invention may be used alone or in the form of mixtures thereof or in admixture with other active substances. They can be advantageously combined with other defoliants, other plant protecting or noxious agents, depending on what effects are sought to be realized. Thus for example the compounds of the invention may be combined with herbicides when it is desired to achieve an inhibition of development of certain weeds, plants, shrubs and the like. Examples of such other active substances include the following: triazine, aminotriazole, anilide, diazine, uracil, aliphatic carboxylic acids and halogeno carboxylic acids, substituted benzoic acids and aryloxycarboxylic acids, hydrazide, amide, nitrile, esters of such carboxylic acids, carbamidic acid and thiocarbamidic acid, esters, 2,3,6-trichlorobenzyloxypropanil, rhodan containing agents and other like compounds.
There may also be included in the agents of the invention other non-phytotoxic aditives which for example with the herbicides provide a synergistic growth regulating effect. Such non-phytotoxic additives include emulsifying agents, dispersing agents, solvents and oil-type additives.
The compositions of the invention can include in their formulation other growth regulating and defoliating agents as for example
Auxin PA0 .alpha.-(2-chlorophenoxy)-propionic acid PA0 4-chlorophenoxyacetic acid PA0 2,4-dichlorophenoxyacetic acid PA0 indolyl-3-acetic acid PA0 indolyl-3-butyric acid PA0 .alpha.-naphthylacetic acid PA0 .beta.-naphthoxyacetic acid PA0 naphthylacetamide PA0 n-m-tolylphthalylamidic acid PA0 gibberelline PA0 S,S,S-tri-n-butyl-trithiophosphoric acid ester PA0 cytokinine PA0 2-chloroethylphosphonic acid PA0 2-chloro-9-hydroxyfluorene-9-carboxylic acid PA0 2-chloroethyl-trimethylammoniumchloride PA0 N,N-dimethylaminosuccinic acid amide PA0 2-isopropyl-4-trimethylammonio-5-methylphenylpiperidine-1-carboxylic acid ester chloride PA0 phenyl-isopropylcarbamate PA0 3-chlorophenyl-isopropylcarbamate PA0 ethyl-2-(3-chlorophenylcarbamoyloxy)-propionate PA0 maleic acid hydrazide PA0 2,3-dichloroisobutyric acid PA0 di-(methoxythiocarbonyl)-disulfide PA0 1,1'-dimethyl-4,4'-bipyridylium-dichloride PA0 3,6-endoxohexahydrophthalic acid, PA0 3-amino-1,2,4-triazole PA0 1,2,3-thiadiazolyl-5-yl-urea derivatives PA0 1-(2-pyridyl)-3-(1,2,3-thiadiazole-5-yl)-urea PA0 2-butylthio-benzthiazole PA0 2-(2(methylpropylthio))-benzthiazole PA0 3,4-dichloroisothiazole-5-carboxylic acid PA0 2,3-dihydro-5,6-dimethyl-1,4-dithiin-1,1,4,4-tetraoxide PA0 arsenic acid PA0 cacodylic acid PA0 chlorate, preferably calciumchlorate, potassiumchlorate PA0 magnesium chlorate or sodium chlorate PA0 calciumcyanamide, PA0 potassium iodide PA0 magnesiumchloride PA0 abietic acid PA0 nonanol PA0 80 weight % active agent PA0 15 weight % kaolin PA0 5 weight % surface active agent on the basis of sodium salts of N-methyl-N-oleyl-taurine and the calcium salt of ligninsulfonic acid. PA0 50 weight % active agent PA0 40 weight % mineral clay PA0 5 weight % cellulose pitch PA0 5 weight % surface active agent on the basis of a mixture of calcium salt of ligninsulfonic acid with alkylphenylpolyglycol ethers. PA0 20 weight % active agent PA0 70 weight % mineral clay PA0 5 weight % cellulose pitch PA0 5 weight % surface active agent on the basis of a mixture of a calcium salt of ligninsulfonic acid with alkylphenylpolyglycol ethers. PA0 5 weight % active agent PA0 80 weight % tonsil PA0 20 weight % cellulose pitch PA0 5 weight % surface active agent on the basis of a fatty acid condensation product. PA0 20 weight % active agent PA0 40 weight % xylene PA0 35 weight % dimethylsulfoxide PA0 5 weight % of a mixture of nonylphenylpolyoxyethylene or calciumdodecylbenzenesulfonate.
As above noted the compounds in the form of their compositions can be used in the form of powders, scatters, granulates, solutions, emulsions or suspensions, with the addition of liquid and/or solid vehicles or diluents as well as wetting, adhesive, emulsifying and/or dispersing agents.
The compositions of the invention can for example be formulated as follows: